Experimental design. Sampling regimen in the EHV-1 infection studies. Experiment 1 consisted of ponies infected with Ab4 (n = 2) or Ab4Δ75-LacZ (n = 8), experiment 2 consisted of horses infected with Ab4 (n = 12), and experiment 3 consisted of horses infected with Ab4 (n = 6) or Ab4GFP (n = 6). Day 0 indicated by the dotted orange line was the time point of experimental infection. Continuous black lines indicate daily exams/sampling, dotted black lines indicate every other day sampling and continuous gray lines with numbers indicate specific sampling points. The X in experiments 1 and 2 indicate euthanasia and post mortem as well as immunohistochemistry (IC), in situ hybridization (ISH) and PCR where indicated.